The equipment used in the automatic processing of certain products functions most efficiently when the products are within a particular size or weight range. In addition, certain parameters such as optimum processing times and temperatures are related to the weight or size of the individual product items being treated. For example, in a poultry processing plant the eviscerating devices are preferably sized to the sizes of the birds being processed so as to remove all of the entrails without damaging the carcasses. Similarly, the optimum dwell period in the chiller tanks is longer for larger birds than for smaller birds.
When processing natural items such as meat carcasses, vegetables, fruits and the like, the individual items are not identical and may vary in size and weight over a considerable range. It has been the practice to utilize apparatus and parameters which provide an acceptable end product without an excessive number of rejects. Greater efficiency would be achieved, however, if the equipment and parameters were related to a narrow size or weight range. For example, two processing lines could be provided, with one line operating most efficiently with relatively small birds and the other line operating most efficiently with relatively large birds.
When processing certain products as, for example, poultry, the average sizes of the birds frequently vary appreciably from one flock to the next, and if the birds were to be sorted with respect to an average or mean size of bird processed over an extended period of time, there would be periods when all of the birds would fall in either the small or large category. If, therefore, separate lines were provided for respectively processing bird carcasses over and under a given size, one such line might be handling most of the carcasses from a given flock being processed while the other line might be virtually empty, and that would be less efficient than the present system of processing all sizes of birds on the same line. It would be desirable, however, to sort the birds being processed at any given time into different size categories for processing on different lines so as to utilize both lines at all times while still using one line primarily for processing small birds and using the other line primarily for processing large birds.
There would be other advantages resulting from the sorting of the birds into two or more sizes and processing the different sized birds on different lines. For example, in a typical processing plant some of the birds are cut up for sale as separate pieces while the others are sold whole. Considerable cost savings would result from cutting up only the larger birds since the labor cost is the same for cutting up both large and small birds yet the overall price differential for cut-up large birds is greater than the price differential for cut-up small birds. Therefore, it would be desirable to cut up only the large birds, provided, of course, that a continuous supply of birds to the cut-up station was provided even though a flock of smaller birds was being processed.